She is very injury prone I agree. I don't have Twitter but there are some very harsh comments about her there, probably not tennis fans. They think she's in the wrong career entirely.
That is Twitter for you. Public figures get major abuse for the least thing. Female politicians get truly vile stuff aimed at them.
In the case of Emma, at 19 she has won one of the biggest prizes in sport, become gobally famous, and is made for life financially. Alas this makes her the target of a huge amount of resentment. Although attitudes to gender have improved in many ways, it is still striking how much spite successful women have directed at them, either in directly misogynist ways, or in the form of more camouflaged sniping.